In this activity, students approach 10,000 by counting up in different ways. Each count ends by reaching 10,000. Students count by different amounts and describe patterns and relationships between numbers. The activity is designed to highlight familiar counting patterns as a way to support naming and writing multi-digit numbers. The final questions in the task ask students to consider the magnitude of each number in relation to 10,000.

When students count by large numbers and examine the counted numbers, they observe patterns in how the different digits in the numbers change (MP7).

• “¿En qué se parecen contar de 100 en 100 y de 1,000 en 1,000 a contar de 1 en 1 y de 10 en 10?” // “How is counting by 100 and 1,000 like counting by 1 and 10?” (When counting by thousands, only the thousands change. This is also the case when counting by ones, tens, and hundreds.)
• Have students share their answers for the last problem.
• Consider asking: “¿Alguien puede expresar de otra forma lo que _____ compartió?” // “Who can restate what _____ shared?”
• If needed, discuss the placement of the comma in each number.

In this activity, students work within 100,000 and determine how many thousands and ten-thousands are in each number. When students use strategies that are based on place value they are looking for and making use of structure (MP7).

• Read each of the numbers in the table chorally. For additional practice saying numbers, have students read the numbers in the last problem as well.
• Discuss students’ responses to the second and fourth columns.
• “¿Cómo se relaciona el número de unidades de mil con el número de unidades de diez mil?” // “How are the number of thousands related to the number of ten-thousands?” (There are 10 groups of thousands in every ten-thousand.)
• If needed, consider using the 10,000 chart created in the last lesson or base-ten blocks to clarify the relationship between the number of thousands and the number of ten-thousands in each five-digit number.